Very small scale reactors and mixers and the like are becoming an important part of the research methodology in materials development as these allow rapid assessment of various materials and chemistries. Symyx Discovery Tools Inc. provides some such tools including a parallel pressure reactor. Applicants have found that existing impellers such as described in U.S. Pat. No. 6,834,990 while providing mixing are not necessarily adequate in many circumstances in these very small reaction chambers. Thus, the need for an improved impeller or stirrer and an apparatus was needed.
Mixing equipment (including impellers) is advantageously tailored in certain circumstances to the process objectives desired for the process under study. Thus a significant variety of impeller designs exist to be used for mixing relatively larger volumes than what pertain in parallel processing high throughput equipment. Such impellers are described in numerous publications by vendors such as Caframo Ltd, IKA Works, and INDCO Mixing equipment. Other mixing elements such as loop stirrers (see e.g., Great Britain Patent Number GB 1450517) are also known. Often the mixing elements are taught to require baffles or other complex geometries in the mixing chamber (see e.g., U.S. Pat. No. 5,102,229; Japanese Patent Application Publication Number JP 08-252445, also known as JP 1996-252445; or Japanese Patent Number 3586685 B2 (family to JP 08281089, also known as JP 1996-281089). Such complex geometries are not well suited to small volume mixers.